1. Field of the Invention
This invention relates to patterned napped sheets and to methods for their production.
2. Description of Prior Art
Artificial suedes having elegant appearance and touch have been widely used. As a result, novel surface appearances are demanded.
Conventional methods for forming a pattern on the nap surface--besides printing with dyestuff--are embossing, singeing after temporary printing with a sizing agent, printing a dissolving or decomposing agent for naps or printing a resin.
However, all of these processes suffer from drawbacks such as decreasing the strength or hardening to the touch. Especially, the surface touch characteristic of ultrafine fibers is seriously damaged on the modified surface. Moreover, in the embossing, a different roll is necessary for every pattern and the other processes necessitate treating agents.
U.S. Pat. No. 4,497,095 disclosed a method for making the appearance of a raised fabric suede-like by jet spraying a high pressure liquid onto the nap surface. However, in this method, conical or sectoral spray was directed to a fabric through a partially closed mesh disposed in spaced relation to the fabric. Thus the U.S. patent disclosed a method for producing the beauty of light and shade on the artificial suede resulting from an anisotropic or random arrangement of the nap as seen with natural suede and, on the other hand, a sharp pattern of the nap surface was not disclosed nor suggested.